In discussing what is known and unknown about the carbon cycle, the authors contend that current and future advances in climate policy depend on a robust infrastructure for science and observation of the carbon cycle, at multiple scales. They add that global and national policy arenas are ripe for greater dialogue between scientists and policy makers about climate mitigation approaches and the advances scientists must make in order to monitor, measure and verify that mitigation actions are working.

Anthropogenic carbon emissions have substantially disturbed the natural global carbon cycle, with the accumulation of carbon in the atmosphere causing climate change. As nations begin to realize the extent of carbon’s impact on the global climate, and respond to the need for long-term climate stabilization with pledges to reduce emissions of carbon dioxide and other greenhouse gases – for example, in discussions at this week’s Conference of the Parties (COP21) in Paris – the researchers suggest that in order for future climate mitigation strategies to be effective, major advances in carbon cycle science are required.

For example, the authors – representing a national cross-section of carbon cycle scientists – state that while reducing fossil fuel use is critical, many unknowns remain about the most efficient ways to accomplish and monitor emission reductions. Developing the most effective, efficient and targeted approaches for reductions in carbon emissions demands continued, interdisciplinary improvement in understanding carbon cycle mechanisms, they add.

In addition, they point out, it is possible that carbon could be stored in land biosphere and aquatic systems, but how to change these systems to make them greater long-term carbon sinks is not well understood. Nevertheless, strategies to enhance such sinks are being seriously considered – for example, as part of the portfolio to meet U.S. emission targets.